Modern vehicles include computer systems for controlling engine emissions, vehicle braking, and a variety of other items. The systems require data in order to function, such as oxygen level data for controlling engine emissions and wheel speed data for controlling braking. This data is generally supplied by sensors located throughout the vehicle. To ensure the integrity of the data provided by the sensors, controllers perform malfunction testing on the sensors (or the signals or data the sensors provide). If a sensor malfunction is detected (in other words, there is an error in the sensor output or sensor data), a warning light or similar indicator can be activated.